Wildfire in California, September 4 to 5, 2002

EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
230 PM PDT WED SEP 4 2002

.SYNOPSIS...SOUTHWEST FLOW ALOFT WILL BRING INCREASING MOISTURE FROM
WEAKENING TROPICAL STORM HERNAN WITH AN INCREASING CHANCE OF SHOWERS OR
THUNDERSTORMS INTO FRIDAY...DECREASING SATURDAY. INCREASING SWELL FROM
HERNAN WILL CAUSE LARGE SURF AND A HIGH SURF ADVISORY IS IN EFFECT
THROUGH FRIDAY...MAINLY FOR SOUTH FACING BEACHES. HIGH ASTRONOMICAL
TIDES COULD ALSO CAUSE SOME LOCAL TIDAL OVERFLOW. DRIER WEST FLOW ALOFT
WILL DEVELOP NEXT WEEK.

.DISCUSSION...LOW CLOUDS AND LOCAL DENSE FOG NEAR THE COAST THIS AM. MID
AND HI LEVEL CLOUDS IN SW FLOW ALOFT AND A FEW SPRINKLES EARLIER TODAY.
12Z NKX SOUNDING HAD A MODERATELY STRONG INVERSION BASED BELOW 1000 FT.
ONSHORE GRADIENTS WITH ABOUT 4 MB SAN-IPL. LOOKS LIKE THERE IS SOME
CHAFF IN THE SOUTHWEST FLOW GIVING LOCALLY STRONG RADAR RETURNS NOT
ASSOCIATED WITH PRECIP.

HERNAN HAS FINALLY TURNED NW AND MOISTURE EXPECTED TO GET ENTRAINED IN
SW FLOW ALOFT AROUND BOTTOM OF TROUGH DEVELOPING OFF THE W COAST. LOOKS
LIKE MOST OF THE MOISTURE WILL GO PAST TO OUR N BUT STILL ENOUGH FOR A
CHANCE OF SHOWERS/THUNDERSTORMS IN ALL OF OUR CWFA STARTING THU AND
CONTINUING INTO SAT. HOWEVER...MOISTURE SHOULD START TO DECREASE SAT.
COMBINATION OF MORE CLOUD COVER THU AND THEN DEEPENING TROUGH FRI/SAT
WILL BRING COOLING TO MOST AREAS. HOWEVER...TROPICAL AIR MASS CAN PLAY
HAVOC WITH TEMPS AND WOULD NOT BE SURPRISED TO SEE SOME LOCAL WARMING
THU IF THERE IS ENOUGH SUNSHINE. LOOKS LIKE RAINFALL TOTALS SHOULD
GENERALLY REMAIN LESS THAN 1/4 INCH...TRENDING A LITTLE MORE TO THE N
AND LESS TO THE S. HOWEVER...THERE IS ALWAYS THE POTENTIAL FOR HEAVIER
RAIN IN THUNDERSTORMS OR ON SW FACING MOUNTAIN SLOPES DEPENDING ON
EXACTLY HOW MUCH MOISTURE MOVES INTO OUR AREA. STILL SOME LOW CLOUDS
OVER THE COASTAL WATERS AND PROBABLY NOT ENOUGH MID/HI CLOUDS TO
COMPLETELY DISRUPT MARINE LAYER TONIGHT BUT SHOULD GET MORE DISRUPTED
THU AND FRI NIGHTS. SLY SWELL FROM HERNAN WILL CONTINUE LARGE SURF AND
S FACING BEACHES AND THIS WILL BE COMBINED WITH HI ASTRONOMICAL TIDES
FOR POSSIBLE TIDAL OVERFLOW THROUGH FRI.

DRIER FLOW ALOFT AND REDEVELOPING MARINE LAYER SUN/MON. INCREASING
HEIGHTS AND POSSIBLE WEAK OFFSHORE FLOW TUE/WED FOR A LITTLE WARMING.

.SAN...HIGH SURF ADVISORY...SEE LAXMWSSGX
       HAZARDOUS WEATHER OUTLOOK...SEE LAXSPSSGX

ATKIN

CAZ042-043-048-050-055>058-060>062-050400-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SAN DIEGO CA
1230 PM PDT WED SEP 4 2002

...CHANCE OF SHOWERS OR THUNDERSTORMS INTO SATURDAY...

MOISTURE FROM WEAKENING TROPICAL STORM HERNAN 850 MILES SOUTHWEST OF
SAN DIEGO WILL MOVE OVER SOUTHWESTERN CALIFORNIA THROUGH SATURDAY. MOST
OF THE MOISTURE WILL MOVE PAST TO THE NORTH BUT THERE WILL BE ENOUGH FOR
A CHANCE OF SHOWERS OR THUNDERSTORMS INTO SATURDAY. THE BEST CHANCE OF
RAIN WILL BE ON FRIDAY.

PRELIMINARY RAINFALL ESTIMATES ARE FOR GENERALLY LESS THAN A QUARTER OF
AN INCH RAIN...WITH A LITTLE HIGHER AMOUNTS TOWARD THE NORTH AND LOWER
AMOUNTS TOWARD THE SOUTH. HOWEVER...THERE COULD BE SOME LOCALLY LARGER
AMOUNTS IN THUNDERSTORMS OR ON SOUTHWEST FACING MOUNTAIN SLOPES. THE
MOISTURE WILL TAPER OFF DURING THE DAY SATURDAY.

THIS COULD BE THE FIRST SIGNIFICANT WIDESPREAD RAINFALL SINCE
APRIL 25...OVER 130 DAYS AGO. ROADS WILL BE SLICK IN THOSE AREAS THAT
GET RAIN. STAY INFORMED FOR FURTHER UPDATES AS THIS WEATHER PATTERN
DEVELOPS.

ATKIN